Drive Shaft Vibration 40-50 mph

Cool. Ill inspect my trans mount. If all appears well, i may replace the rear u joint for preventative maintanace/ elimination. Really hoping it is not axle bearings.

 

Pull the shaft off and move each end thru it's entire range of motion. Look for any play or binding. Nothing less than zero play and totally smooth movement is what you want.
This costs nothing more than time.

 

This is how I was able to determine a single needle bearing on my rear joint was bad. It seemed perfectly fine and solid while it was attached.

 

OP, also when "eyeballing" pinion angle, adjust your perspective to a point dead nuts perpendicular to and level with the diff flange. Your pic "looks OK" but the perspective is off.

 

Will do, i will post a follow up picture

 

Since the thread isn't too old, a couple other things to inspect. I'm guessing your truck has higher miles. Sometimes the spine joint wears and becomes sloppy fitting. If you push and pull on the spline joint while under the truck, it shouldn't give at all. If you feel any slop, it's too much. A driveshaft shop can put a new spline on, and it doesn't really cost that much. (I took the front driveshaft on my '11 into the shop. They pulled it apart and inspected the spline, and told me that there wasn't really any grease on the spline. The driveshaft factory didn't put anywhere near enough in.)

Also look for dents in the driveshaft. I don't know if you drive off road, but dents can throw the shaft out of balance. Also, if you drive off road, the balancing weights on the driveshaft could possibly get knocked off. Not likely, but they are tack welded on, so it's possible.

 

I had this exact issue and it was resolved by replacing a couple of the U joints that had some play in them and Rebuilding the Center driveshaft bearing mechanism. This happend at 310K miles. Its running perfectly now.

 

Did you service the double cardan joint or was it a full replacement with a spicer or similar joint?

 

I'm not a mechanic but here are pictures of what they worked on: